by James R. Healey, USA TODAY

by James R. Healey, USA TODAY

A lawsuit over Ford's heavily advertised EcoBoost engines is the latest bit of tarnish on the carefully crafted image of the engines as premium units worth a premium price.

Ford has sold some 700,000 engines with the EcoBoost label, about 400,000 of those being the 3.5-liter V-6 in F-150 pickups, where it can add $2,395 to the price, in return for more power and slightly better fuel economy than the less-expensive 5-liter V-8 option.

But now, some owners of that 3.5-liter V-6 EcoBoost engine, also used in some Lincolns and Ford cars and SUVs, have sued Ford because the engine doesn't run right, they say.

Ford won't discuss the lawsuit, but the symptoms it cites - stalling and power loss - match complaints that Ford addressed last year in a bulletin to dealers, and by making a running change on the assembly line. That bulletin tells mechanics how to fix "Intermittent stumble and/or misfire" that is "more noticeable during humid or damp conditions" and "intermittent engine surge during moderate to light loads" in 3.5-liter V-6 EcoBoost engines.

Even if it's a simple matter of getting dealers to update the cars owned by the people suing, headlines about the suit taint the EcoBoost name that, the automaker says, has boosted its appeal among potential buyers.

"We're committed to the EcoBoost brand, which is important to Ford," says spokesman Mark Schirmer.

EcoBoost is Ford's marketing term for engines that use turbocharging and direct injection and are smaller-displacement than has been typical. The EcoBoost name has been tarnished several times before now.

â?¢ In February, Consumer Reports found that many of today's turbocharged engines fail to live up to their advertised promises of better fuel economy and strong performance. Ford's Fusion with 1.6-liter EcoBoost became the chief bad example, being "among the worst" in real-world mileage among midsize sedans, including some powered by conventional, non-turbo, larger-displacement, four-cylinder engines.

â?¢ Last year, Fusion and Escape SUVs with 1.6-liter four-cylinder EcoBoost engines were recalled several times for coolant and fuel leaks that could result in fires.

But Ford might have a Teflon coating. Not only are Escapes and Fusions selling well despite the earlier recalls, demand for the formerly troubled 1.6 EcoBoost is so strong that Ford is adding a 1.5-liter four-cylinder that it makes elsewhere to the lineup because it can't make enough 1.6-liter EcoBoost engines to keep up.

"Everybody has issues these days. It's Ford's turn," says Phil Gott, a senior director at consultant IHS Automotive. "It's not going to help, but it's not a terminal issue." There's nothing inherently troublesome about the technology that comprises EcoBoost, he says, and the key for an automaker with a problem is to take care of aggrieved owners very well.

Ford believes it did that in the previous recalls and in the case of 3.5-liter EcoBoost stumbles, though the three Ohio Ford owners who are suing surely would disagree.

While EcoBoost isn't as well-known as Chrysler's "Hemi" name for its large-displacement V-8, being able to advertise EcoBoost engines nonetheless seems to be helping power Ford sales not only among mainstream buyers, but also in markets where it's been doing poorly.

Fusions, nearly all of which have EcoBoost 1.6- or 2-liter, four-cylinder engines, are zooming in import-favoring California, says Ford sales analyst Erich Merkle. "Fusion sales in California are up 117%" January through April, he says, and "in April, they're up 146%." One reason: "The EcoBoost mileage."

EcoBoost-equipped Fusions are rated from 26 mpg to 29 mpg in combined city/highway driving in government tests, and as much as 37 mpg on the highway, which is the number automakers like to advertise.